HTML code of the example :

<HTML>
<input type="text" id="example-1-tf"/>
</HTML>

Javascript code is really simple:

<script type="text/javascript">
new Calendar('example-1', {
    source:'example-1-tf'
});
</script>

<input type="text" id="example-1-tf"/>
<span class="info">(Try the Arrow Keys and Page Up/Page Down to browse dates)</span>